Phenol-alkoxylate co-solvent surfactant composition

ABSTRACT

Provided herein are, inter alia, compositions including a surfactant and a phenol-alkoxylate co-solvent useful in enhanced oil recovery. The compositions and methods provided herein are particularly useful for oil recovery under a broad range of reservoir conditions (e.g. high to low temperatures, high to low salinity, highly viscous oils).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/770,949 filed Feb. 28, 2013, which is hereby incorporated in itsentirety and for all purposes.

BACKGROUND OF THE INVENTION

Enhanced Oil Recovery (abbreviated EOR) refers to techniques forincreasing the amount of unrefined petroleum, or crude oil that may beextracted from an oil reservoir (e.g. an oil field). Using EOR, 40-60%of the reservoir's original oil can typically be extracted compared withonly 20-40% using primary and secondary oil recovery methods (e.g. bywater injection or natural gas injection). Enhanced oil recovery mayalso be referred to as improved oil recovery or tertiary oil recovery(as opposed to primary and secondary oil recovery).

Enhanced oil recovery may be achieved by a variety of methods includingmiscible gas injection (which includes carbon dioxide flooding),chemical injection (which includes polymer flooding, alkaline floodingand surfactant flooding), microbial injection, or thermal recovery(which includes cyclic steam, steam flooding, and fire flooding). Theinjection of various chemicals, usually as dilute aqueous solutions, hasbeen used to improve oil recovery. Injection of alkaline or causticsolutions into reservoirs with oil that has organic acids or acidprecursors naturally occurring in the oil will result in the productionof soap (i.e. in situ generated soap) that may lower the interfacialtension enough to increase production. Injection of a dilute solution ofa water soluble polymer to increase the viscosity of the injected watercan increase the amount of oil recovered in some formations. Dilutesolutions of surfactants such as petroleum sulfonates may be injected tolower the interfacial tension or capillary pressure that impedes oildroplets from moving through a reservoir. Special formulations of oil,water and surfactant microemulsions, have also proven useful.Application of these methods is usually limited by the cost of thechemicals and their adsorption and loss onto the rock of the oilcontaining formation.

Some unrefined petroleum contains carboxylic acids having, for example,C₁₁ to C₂₀ alkyl chains, including napthenic acid mixtures. The recoveryof such “reactive” oils may be performed using alkali (e.g. NaOH orNa₂CO₃) in a surfactant composition. The alkali reacts with the acid inthe reactive oil to form soap in situ. These in situ generated soapsserve as an additional source of surfactants enabling the use of muchlower level of surfactants initially added to effect enhanced oilrecovery (EOR). However, when the available water supply is hard, theadded alkali causes precipitation of cations, such as Ca⁻² or Mg⁺². Inorder to prevent such precipitation an expensive chelant such as EDTAmay be required in the surfactant composition. Alternatively, watersoftening processes may be used.

Therefore, there is a need in the art for cost effective methods forenhanced oil recovery using chemical injection. Provided herein aremethods and compositions addressing these and other needs in the art.

BRIEF SUMMARY OF THE INVENTION

The compositions provided herein include a surfactant and a co-solventhaving the formula I, II, or III and are particularly useful for oilrecovery under a broad range of reservoir conditions (e.g. high to lowtemperatures, high to low salinity, highly viscous oils). Compared toexisting surfactant compositions used in the art, the aqueouscompositions according to the embodiments provided herein are highlyversatile and cost effective.

In one aspect, an aqueous composition including water, a surfactant anda co-solvent having the formula:

is provided. In formula (I) R¹ is independently hydrogen orunsubstituted C₁-C₆ alkyl, R² is independently hydrogen or unsubstitutedC₁-C₂ alkyl and n is an integer from 1 to 30.

In one aspect, an aqueous composition including water, a surfactant anda co-solvent having the formula:

In formula (IA) R¹ is independently hydrogen, unsubstituted C₁-C₆ alkylor R⁵—OH, R² is independently hydrogen or unsubstituted C₁-C₂ alkyl, R⁵is independently a bond or unsubstituted C₁-C₆ alkyl, n is an integerfrom 1 to 30, o is an integer from 1 to 5 and z is an integer from 1 to5.

In another aspect, an emulsion composition including an unrefinedpetroleum phase and an aqueous phase is provided. In the emulsioncomposition the aqueous phase includes water, a surfactant and aco-solvent having the formula

In formula (I) R¹ is independently hydrogen or unsubstituted C₁-C₆alkyl, R² is independently hydrogen or unsubstituted C₁-C₂ alkyl, and nis an integer from 1 to 30.

In another aspect, a method of displacing an unrefined petroleummaterial in contact with a solid material is provided. The methodincludes (i) contacting an unrefined petroleum material with the aqueouscomposition as provided herein including embodiments thereof, whereinthe unrefined petroleum material is in contact with a solid material.The unrefined petroleum material is allowed to separate from the solidmaterial thereby displacing the unrefined petroleum material in contactwith the solid material.

In another aspect, a method of converting an unrefined petroleum acidinto a surfactant is provided. The method includes contacting apetroleum material with the aqueous composition as provided hereinincluding embodiments thereof, thereby forming an emulsion in contactwith the petroleum material. The unrefined petroleum acid within theunrefined petroleum material is allowed to enter into the emulsion,thereby converting the unrefined petroleum acid into a surfactant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Phase behavior activity (0.2% C₂₈-45PO-10EO carboxylate, 0.3%C₁₉₋₂₈ IOS, 0.5% IBA-3EO) plot with Oil #2 at 100° C. after 24 days and30% oil. The black arrow in the histogram pointing from left to rightindicates the aqueous stability at 3.0% NaBO₂.

FIG. 2. Phase behavior activity (0.2% C₂₈-45PO-10EO carboxylate, 0.3%C₁₉₋₂₈ IOS, 0.25% Phenol-6EO) plot with Oil #2 at 100° C. after 21 daysand 30% oil. The black arrow in the histogram pointing from left toright indicates the aqueous stability at 2.5% NaBO₂.

FIG. 3. Phase behavior activity (0.5% C₁₉₋₂₃ IOS, 0.5% C₁₂₋₁₃13PO-sulfate, 1% IBA-5EO) plot with Oil #1 at 55° C. after 17 days and30% oil. The black arrow in the histogram pointing from left to rightindicates the aqueous stability at 48,000 ppm (TDS).

FIG. 4. Phase behavior activity (0.5% C₁₉₋₂₃ IOS, 0.5% C₁₂₋₁₃13PO-sulfate, 0.5% Phenol-6EO) plot with Oil #1 at 55° C. after 34 daysand 30% oil. The black arrow in the histogram pointing from left toright indicates the aqueous stability at 46,000 ppm (TDS).

DETAILED DESCRIPTION OF THE INVENTION I. DEFINITIONS

The abbreviations used herein have their conventional meaning within thechemical and biological arts.

Where substituent groups are specified by their conventional chemicalformulae, written from left to right, they equally encompass thechemically identical substituents that would result from writing thestructure from right to left, e.g., —CH₂O— is equivalent to —OCH₂—.

The term “alkyl,” by itself or as part of another substituent, means,unless otherwise stated, a straight (i.e. unbranched) or branched chainwhich may be fully saturated, mono- or polyunsaturated and can includedi- and multivalent radicals, having the number of carbon atomsdesignated (i.e. C₁-C₁₀ means one to ten carbons). Examples of saturatedhydrocarbon radicals include, but are not limited to, groups such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl,sec-butyl, homologs and isomers of, for example, n-pentyl, n-hexyl,n-heptyl, n-octyl, and the like. An unsaturated alkyl group is onehaving one or more double bonds or triple bonds. Examples of unsaturatedalkyl groups include, but are not limited to, vinyl, 2-propenyl, crotyl,2-isopentenyl, 2-(butadienyl), 2,4-pentadienyl, 3-(1,4-pentadienyl),ethynyl, 1- and 3-propynyl, 3-butynyl, and the higher homologs andisomers. Alkyl groups which are limited to hydrocarbon groups are termed“homoalkyl”. An alkoxy is an alkyl attached to the remainder of themolecule via an oxygen linker (—O—).

The term “alkylene” by itself or as part of another substituent means adivalent radical derived from an alkyl, as exemplified, but not limited,by —CH₂CH₂CH₂CH₂—, and further includes those groups described below as“heteroalkylene. ” Typically, an alkyl (or alkylene) group will havefrom 1 to 24 carbon atoms, with those groups having 10 or fewer carbonatoms being preferred in the present invention. A “lower alkyl” or“lower alkylene” is a shorter chain alkyl or alkylene group, generallyhaving eight or fewer carbon atoms.

The term “heteroalkyl,” by itself or in combination with another term,means, unless otherwise stated, a stable straight or branched chain orcombinations thereof, consisting of at least one carbon atom and atleast one heteroatom selected from the group consisting of O, N, P, Siand S. The heteroatom(s) O, N, P and S and Si may be placed at anyinterior position of the heteroalkyl group or at the position at whichthe alkyl group is attached to the remainder of the molecule. Examplesinclude, but are not limited to, —CH₂—CH₂—O—CH₃, —CH₂—CH₂—NH—CH₃,—CH₂—CH₂—N(CH₃)—CH₃, —CH₂—S—CH₂—CH₃, —CH₂—CH₂, —S(O)—CH₃,—CH₂—CH₂—S(O)₂—CH₃, CH═CH—O—CH₃, —Si(CH₃)₃, —CH₂—CH═N—OCH₃,—CH═CH—N(CH₃)—CH₃, O—CH₃, —O—CH₂—CH₃, and —CN. Up to two heteroatoms maybe consecutive, such as, for example, —CH₂—NH—OCH₃. Similarly, the term“heteroalkylene” by itself or as part of another substituent means adivalent radical derived from heteroalkyl, as exemplified, but notlimited by, —CH₂—CH₂—S—CH₂—CH₂— and —CH₂—S—CH₂—CH₂—NH—CH₂—. Forheteroalkylene groups, heteroatoms can also occupy either or both of thechain termini (e.g., alkyleneoxy, alkylenedioxy, alkyleneamino,alkylenediamino, and the like). Still further, for alkylene andheteroalkylene linking groups, no orientation of the linking group isimplied by the direction in which the formula of the linking group iswritten. For example, the formula —C(O)₂R′— represents both —C(O)₂R′—and —R′C(O)₂—.

The terms “cycloalkyl” and “heterocycloalkyl,” by themselves or incombination with other terms, represent, unless otherwise stated, cyclicversions of “alkyl” and “heteroalkyl,” respectively. Additionally, forheterocycloalkyl, a heteroatom can occupy the position at which theheterocycle is attached to the remainder of the molecule. Examples ofcycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, 1-cyclohexenyl, 3-cyclohexenyl, cycloheptyl,and the like. Examples of heterocycloalkyl include, but are not limitedto, 1 41,2,5,6-tetrahydropyridyl), 1-piperidinyl, 2-piperidinyl,3-piperidinyl, 4-morpholinyl, 3-morpholinyl, tetrahydrofuran-2-yl,tetrahydrofuran-3-yl, tetrahydrothien-2-yl, tetrahydrothien-3-yl,1-piperazinyl, 2-piperazinyl, and the like. A “cycloalkylene” and a“heterocycloalkylene,” alone or as part of another substituent means adivalent radical derived from a cycloalkyl and heterocycloalkyl,respectively.

The term “aryl” means, unless otherwise stated, a polyunsaturated,aromatic, hydrocarbon substituent which can be a single ring or multiplerings (preferably from 1 to 3 rings) which are fused together (i.e. afused ring aryl) or linked covalently. A fused ring aryl refers tomultiple rings fused together wherein at least one of the fused rings isan aryl ring. The term “heteroaryl” refers to aryl groups (or rings)that contain from one to four heteroatoms selected from N, O, and S,wherein the nitrogen and sulfur atoms are optionally oxidized, and thenitrogen atom(s) are optionally quaternized. Thus, the term “heteroaryl”includes fused ring heteroaryl groups (i.e. multiple rings fusedtogether wherein at least one of the fused rings is a heteroaromaticring). A 5,6-fused ring heteroarylene refers to two rings fusedtogether, wherein one ring has 5 members and the other ring has 6members, and wherein at least one ring is a heteroaryl ring. Likewise, a6,6-fused ring heteroarylene refers to two rings fused together, whereinone ring has 6 members and the other ring has 6 members, and wherein atleast one ring is a heteroaryl ring. And a 6,5-fused ring heteroarylenerefers to two rings fused together, wherein one ring has 6 members andthe other ring has 5 members, and wherein at least one ring is aheteroaryl ring. A heteroaryl group can be attached to the remainder ofthe molecule through a carbon or heteroatom. Non-limiting examples ofaryl and heteroaryl groups include phenyl, 1-naphthyl, 2-naphthyl,4-biphenyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 3-pyrazolyl,2-imidazolyl, 4-imidazolyl, pyrazinyl, 2-oxazolyl, 4-oxazolyl,2-phenyl-4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl,5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-furyl, 3-furyl,2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidyl,4-pyrimidyl, 5-benzothiazolyl, purinyl, 2-benzimidazolyl, 5-indolyl,1-isoquinolyl, 5-isoquinolyl, 2-quinoxalinyl, 5-quinoxalinyl,3-quinolyl, and 6-quinolyl. Substituents for each of the above notedaryl and heteroaryl ring systems are selected from the group ofacceptable substituents described below. An “arylene” and a“heteroarylene,” alone or as part of another substituent means adivalent radical derived from an aryl and heteroaryl, respectively.

The term “oxo” as used herein means an oxygen that is double bonded to acarbon atom.

Each R-group as provided in the formulae provided herein can appear morethan once. Where a R-group appears more than once ach R group can beoptionally different.

The term “contacting” as used herein, refers to materials or compoundsbeing sufficiently close in proximity to react or interact. For example,in methods of contacting a hydrocarbon material bearing formation and/ora well bore, the term “contacting” includes placing an aqueouscomposition (e. g. chemical, surfactant or polymer) within a hydrocarbonmaterial bearing formation using any suitable manner known in the art(e.g., pumping, injecting, pouring, releasing, displacing, spotting orcirculating the chemical into a well, well bore or hydrocarbon bearingformation).

The terms “unrefined petroleum” and “crude oil” are used interchangeablyand in keeping with the plain ordinary usage of those terms. “Unrefinedpetroleum” and “crude oil” may be found in a variety of petroleumreservoirs (also referred to herein as a “reservoir,” “oil fielddeposit” “deposit” and the like) and in a variety of forms includingoleaginous materials, oil shales (i.e. organic-rich fine-grainedsedimentary rock), tar sands, light oil deposits, heavy oil deposits,and the like. “Crude oils” or “unrefined petroleums” generally refer toa mixture of naturally occurring hydrocarbons that may be refined intodiesel, gasoline, heating oil, jet fuel, kerosene, and other productscalled fuels or petrochemicals. Crude oils or unrefined petroleums arenamed according to their contents and origins, and are classifiedaccording to their per unit weight (specific gravity). Heavier crudesgenerally yield more heat upon burning, but have lower gravity asdefined by the American Petroleum Institute (API) and market price incomparison to light (or sweet) crude oils. Crude oil may also becharacterized by its Equivalent Alkane Carbon Number (EACN).

Crude oils vary widely in appearance and viscosity from field to field.They range in color, odor, and in the properties they contain. While allcrude oils are mostly hydrocarbons, the differences in properties,especially the variation in molecular structure, determine whether acrude oil is more or less easy to produce, pipeline, and refine. Thevariations may even influence its suitability for certain products andthe quality of those products. Crude oils are roughly classified introthree groups, according to the nature of the hydrocarbons they contain.(i) Paraffin based crude oils contain higher molecular weight paraffins,which are solid at room temperature, but little or no asphaltic(bituminous) matter. They can produce high-grade lubricating oils. (ii)Asphaltene based crude oils contain large proportions of asphalticmatter, and little or no paraffin. Some are predominantly naphthenes andso yield lubricating oils that are sensitive to temperature changes thanthe paraffin-based crudes. (iii) Mixed based crude oils contain bothparaffin and naphthenes, as well as aromatic hydrocarbons. Most crudeoils fit this latter category.

“Reactive” crude oil as referred to herein is crude oil containingnatural organic acidic components (also referred to herein as unrefinedpetroleum acid) or their precursors such as esters or lactones. Thesereactive crude oils can generate soaps (carboxylates) when reacted withalkali. More terms used interchangeably for crude oil throughout thisdisclosure are hydrocarbon material or active petroleum material. An“oil bank” or “oil cut” as referred to herein, is the crude oil thatdoes not contain the injected chemicals and is pushed by the injectedfluid during an enhanced oil recovery process. A “nonactive oil,” asused herein, refers to an oil that is not substantially reactive orcrude oil not containing significant amounts of natural organic acidiccomponents or their precursors such as esters or lactones such thatsignificant amounts of soaps are generated when reacted with alkali. Anonactive oil as referred to herein includes oils having an acid numberof less than 0.5 mg KOH/g of oil.

“Unrefined petroleum acids” as referred to herein are carboxylic acidscontained in active petroleum material (reactive crude oil). Theunrefined petroleum acids contain C₁₁ to C₂₀ alkyl chains, includingnapthenic acid mixtures. The recovery of such “reactive” oils may beperformed using alkali (e.g. NaOH or Na₂CO₃) in a surfactantcomposition. The alkali reacts with the acid in the reactive oil to formsoap in situ. These in situ generated soaps serve as a source ofsurfactants minimizing the levels of added surfactants, thus enablingefficient oil recovery from the reservoir.

The term “polymer” refers to a molecule having a structure thatessentially includes the multiple repetitions of units derived, actuallyor conceptually, from molecules of low relative molecular mass. In someembodiments, the polymer is an oligomer.

The term “bonded” refers to having at least one of covalent bonding,hydrogen bonding, ionic bonding, Van Der Waals interactions, piinteractions, London forces or electrostatic interactions.

The term “productivity” as applied to a petroleum or oil well refers tothe capacity of a well to produce hydrocarbons (e.g. unrefinedpetroleum); that is, the ratio of the hydrocarbon flow rate to thepressure drop, where the pressure drop is the difference between theaverage reservoir pressure and the flowing bottom hole well pressure(i.e., flow per unit of driving force).

The term “solubility” or “solubilization” in general refers to theproperty of a solute, which can be a solid, liquid or gas, to dissolvein a solid, liquid or gaseous solvent thereby forming a homogenoussolution of the solute in the solvent. Solubility occurs under dynamicequilibrium, which means that solubility results from the simultaneousand opposing processes of dissolution and phase joining (e.g.precipitation of solids). The solubility equilibrium occurs when the twoprocesses proceed at a constant rate. The solubility of a given solutein a given solvent typically depends on temperature. For many solidsdissolved in liquid water, the solubility increases with temperature. Inliquid water at high temperatures, the solubility of ionic solutes tendsto decrease due to the change of properties and structure of liquidwater. In more particular, solubility and solubilization as referred toherein is the property of oil to dissolve in water and vice versa.

“Viscosity” refers to a fluid's internal resistance to flow or beingdeformed by shear or tensile stress. In other words, viscosity may bedefined as thickness or internal friction of a liquid. Thus, water is“thin”, having a lower viscosity, while oil is “thick,” having a higherviscosity. More generally, the less viscous a fluid is, the greater itsease of fluidity.

The term “salinity” as used herein, refers to concentration of saltdissolved in a aqueous phases. Examples for such salts are withoutlimitation, sodium chloride, magnesium and calcium sulfates, andbicarbonates. In more particular, the term salinity as it pertains tothe present invention refers to the concentration of salts in brine andsurfactant solutions.

An “alkali agent” is used according to its conventional meaning andincludes basic, ionic salts of alkali metals or alkaline earth metals.Alkali agents as provided herein are typically capable of reacting withan unrefined petroleum acid (e.g. the acid in crude oil (reactive oil))to form soap (a surfactant salt of a fatty acid) in situ. These in situgenerated soaps serve as a source of surfactants causing a reduction ofthe interfacial tension of the oil in water emulsion, thereby reducingthe viscosity of the emulsion. Examples of alkali agents useful for theprovided invention include, but are not limited to, sodium hydroxide,sodium carbonate, sodium silicate, sodium metaborate, and EDTAtetrasodium salt.

A “microemulsion” as referred to herein is a thermodynamically stablemixture of oil, water, and a stabilizing agents such as a surfactant ora co-solvent that may also include additional components such as alkaliagents, polymers (e.g. water-soluble polymers) and a salt. In contrast,a “macroemulsion” as referred to herein is a thermodynamically unstablemixture of oil and water that may also include additional components. An“emulsion” as referred to herein may be a microemulsion or amacroemulsion.

II. COMPOSITIONS

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not limit the scope of the invention.

Provided herein, inter alia, are aqueous compositions and methods ofusing the same for a variety of applications including enhanced oilrecovery. The aqueous compositions provided herein may be used withbroad oil concentrations, and at a wide range of salinities, includinghigh salinities such as hard brine. The aqueous compositions accordingto the embodiments provided herein further promote the formation ofemulsions and reduce the viscosity (interfacial viscosity as well asbulk viscosity) of such emulsions, resulting in high oil recoveryefficiencies. The compositions provided herein are particularly usefulfor the recovery of heavy oils (e.g. oils with less than 20° API gravityor a viscosity of more than 400 mPa s).

In one aspect, an aqueous composition including water, a surfactant anda co-solvent having the formula:

(I) is provided. In formula (I) R¹ is independently hydrogen orunsubstituted C₁-C₆ alkyl, R² is independently hydrogen or unsubstitutedC₁-C₂ alkyl and n is an integer from 1 to 30. In some embodiments, R¹ isunsubstituted C₂-C₆ alkyl. In some embodiments, R¹ is unsubstitutedC₁-C₆ alkyl. In some embodiments, R¹ is unsubstituted C₁-C₅ alkyl. Inother embodiments, R¹ is unsubstituted C₁-C₄ alkyl. In otherembodiments, R¹ is unsubstituted C₁-C₃ alkyl. In some embodiments, R¹ isunsubstituted C₁-C₂ alkyl. In some embodiments, R¹ is unsubstituted C₂alkyl. In other embodiments, R¹ is ethyl. In some embodiments, R¹ ismethyl. In some embodiment, R¹ is hydrogen.

R¹ may be linear or branched unsubstituted alkyl. In one embodiment, R¹of formula (I) is linear unsubstituted C₁-C₆ alkyl. In one embodiment,R¹ of formula (I) is branched unsubstituted C₁-C₆ alkyl. In otherembodiments, R¹ of formula (I) is linear unsubstituted C₁-C₅ alkyl. Inother embodiments, R¹ of formula (I) is branched unsubstituted C₁-C₅alkyl. In other embodiments, R¹ of formula (I) is linear unsubstitutedC₁-C₄ alkyl. In other embodiments, R¹ of formula (I) is branchedunsubstituted C₁-C₄ alkyl. In other embodiments, R¹ of formula (I) islinear unsubstituted C₁-C₃ alkyl. In other embodiments, R¹ of formula(I) is branched unsubstituted C₁-C₃ alkyl. In other embodiments, R¹ offormula (I) is linear unsubstituted ethyl. In other embodiments, R¹ offormula (I) is branched unsubstituted ethyl.

In one embodiment, where R¹ is linear or branched unsubstituted alkyl(e.g. branched unsubstituted C₁-C₆ alkyl), the alkyl is a saturatedalkyl (e.g. a linear or branched unsubstituted saturated alkyl orbranched unsubstituted C₁-C₆ saturated alkyl). A “saturated alkyl,” asused herein, refers to an alkyl consisting only of hydrogen and carbonatoms that are bonded exclusively by single bonds. Thus, in oneembodiment, R¹ is linear or branched unsubstituted saturated alkyl. Inone embodiment, R¹ of formula (I) is linear unsubstituted saturatedC₁-C₆ alkyl. In one embodiment, R¹ of formula (I) is branchedunsubstituted saturated C₁-C₆ alkyl. In other embodiments, R¹ of formula(I) is linear unsubstituted saturated C₁-C₅ alkyl. In other embodiments,R¹ of formula (I) is branched unsubstituted saturated C₁-C₅ alkyl. Inother embodiments, R¹ of formula (I) is linear unsubstituted saturatedC₁-C₄ alkyl. In other embodiments, R¹ of formula (I) is branchedunsubstituted saturated C₁-C₄ alkyl. In other embodiments, R¹ of formula(I) is linear unsubstituted saturated C₁-C₃ alkyl. In other embodiments,R¹ of formula (I) is branched unsubstituted saturated C₁-C₃ alkyl. Inother embodiments, R¹ of formula (I) is linear unsubstituted saturatedethyl. In other embodiments, R¹ of formula (I) is branched unsubstitutedsaturated ethyl.

The symbol n is an integer from 1 to 30. In one embodiment, n is aninteger from 1 to 25. In one embodiment, n is an integer from 1 to 20.In one embodiment, n is an integer from 1 to 15. In one embodiment, n isan integer from 1 to 10. In one embodiment, n is an integer from 1 to 5.In some embodiment, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. Inone embodiment, n is 3. In other embodiments, n is 5. In one embodiment,n is 6.

In some embodiments, R¹ is hydrogen. In other related embodiments, n isas defined in an embodiment above (e.g. n is at least 1, or at least 20,e.g. 5 to 15). Thus, in some embodiments, R¹ is hydrogen and n is 6.

In some embodiments, R¹ is methyl. In other related embodiments, n is asdefined in an embodiment above (e.g. n is at least 1, or at least 20,e.g. 5 to 10). Thus, in some embodiments, R¹ is methyl and n is 6.

In one aspect, an aqueous composition including water, a surfactant anda co-solvent having the formula:

In formula (IA) R¹ is independently hydrogen, unsubstituted C₁-C₆ alkylor R⁵—OH, R² is independently hydrogen or unsubstituted C₁-C₂ alkyl, R⁵is independently a bond or unsubstituted C₁-C₆ alkyl, n is an integerfrom 1 to 30, o is an integer from 1 to 5 and z is an integer from 1 to5. In some embodiments, R¹ is unsubstituted C₂-C₆ alkyl. In someembodiments, R¹ is unsubstituted C₄-C₆ alkyl. In some embodiments, R¹ isunsubstituted C₁-C₅ alkyl. In other embodiments, R¹ is unsubstitutedC₁-C4 alkyl. In other embodiments, R¹ is unsubstituted C₁-C₃ alkyl. Insome embodiments, R¹ is unsubstituted C₁-C₂ alkyl. In some embodiments,R¹ is unsubstituted C₂ alkyl. In other embodiments, R¹ is ethyl. In someembodiments, R¹ is methyl. In some embodiment, R¹ is hydrogen.

In some embodiment, R¹ is independently a bond or R⁵—OH. In someembodiment, R¹ is R⁵—OH. In some embodiments, R⁵ is unsubstituted C₂-C₆alkyl. In some embodiments, R⁵ is unsubstituted C₄-C₆ alkyl. In someembodiments, R⁵ is unsubstituted C₁-C₅ alkyl. In other embodiments, R⁵is unsubstituted C₁-C₄ alkyl. In other embodiments, R⁵ is unsubstitutedC₁-C₃ alkyl. In some embodiments, R⁵ is unsubstituted C₁-C₂ alkyl. Insome embodiments, R⁵ is unsubstituted C2 alkyl. In other embodiments, R⁵is ethyl. In some embodiments, R⁵ is methyl. In some embodiments, R⁵ isa bond.

In formula (IA) the symbol n is an integer from 1 to 30. In oneembodiment, n is an integer from 1 to 25. In one embodiment, n is aninteger from 1 to 20. In one embodiment, n is an integer from 1 to 15.In one embodiment, n is an integer from 1 to 10. In one embodiment, n isan integer from 1 to 5. In some embodiment, n is 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,27, 28, 29, or 30. In one embodiment, n is 3. In other embodiments, n is5. In one embodiment, n is 6. In one embodiment, n is 16.

In formula (IA) the symbol o is an integer from 1 to 5 and the symbol zis an integer from 1 to 5. In embodiments, o is 1, 2, 3, 4, or 5. Inembodiments, z is 1, 2, 3, 4, or 5. In embodiments, o is 1 and z is 5.In further embodiments, R¹ is independently hydrogen or R⁵—OH and R⁵ isa bond. In other further embodiments, R¹ is hydrogen. In other furtherembodiments, R¹ is R⁵—OH and R⁵ is a bond.

In formula (I), (IA), (II) or (III) R² may be independently hydrogen orunsubstituted C₁-C₂ alkyl. In some embodiments, R² is hydrogen orunsubstituted C₁ or C₂ alkyl. In some related embodiments, R² ishydrogen or branched unsubstituted C₁ or C₂ saturated alkyl. In someembodiments, R² is hydrogen or a branched unsubstituted C₁ saturatedalkyl. In some embodiments, R² is independently hydrogen or methyl. Inother embodiments, R² is independently hydrogen or ethyl. In someembodiments, R² is independently hydrogen, methyl or ethyl. In someembodiments, R² is hydrogen. In some embodiments, R² is methyl. In someembodiments, R² is ethyl. In formula (I) R² can appear more than onceand can be optionally different. For example, in some embodiments wheren is 3, R² appears three times and can be optionally different. In otherembodiments, where n is 6, R² appears six times and can be optionallydifferent.

In some embodiments, where multiple R² substituents are present and atleast two R² substituents are different, R² substituents with the fewestnumber of carbons are present at the side of the compound of formula(I), (IA), (II) or (III) bound to the —OH group. In this embodiment, thecompound of formula (I), (IA), (II) or (III) will be increasinglyhydrophilic in progressing from the R¹ substituent to the side of thecompound of formula (I), (IA), (II) or (III) bound to the —OH group. Theterm “side of the compound of formula (I), (IA), (II) or (III) bound tothe —OH group” refers to the side of the compound indicated by asterisksin the below structures:

In some embodiments, R² is hydrogen. In other related embodiments, n isas defined in an embodiment above (e.g. n is at least 1, or at least 20,e.g. 5 to 15). Thus, in some embodiments, R² is hydrogen and n is 6.

In some embodiments, R² is methyl. In other related embodiments, n is asdefined in an embodiment above (e.g. n is at least 1, or at least 20,e.g. 5 to 10). Thus, in some embodiments, R² is methyl and n is 6.

In some embodiment, the co-solvent has the formula:

In formula (II) R¹ is defined as above (e.g. unsubstituted C₁-C₆ alkyl),R² is methyl or ethyl, o is an integer from 0 to 15 and p is an integerfrom 1 to 10. In some embodiments, R² is methyl. In other embodiments,R² is ethyl. In formula (II) R² can appear more than once and can beoptionally different. For example, in some embodiments where o is 3, R²appears three times and can be optionally different. In otherembodiments, where o is 6, R² appears six times and can be optionallydifferent.

In some embodiments, o is 0 to 15. In some related embodiments, o is 0to 12. In some related embodiments, o is 0 to 10. In some relatedembodiments, o is 0 to 8. In some related embodiments, o is 0 to 6. Insome related embodiments, o is 0 to 4. In some related embodiments, o is0 to 2. In still further related embodiments, o is 0. In some furtherrelated embodiment, p is 1 to 10. In some further related embodiment, pis 1 to 8. In some further related embodiment, p is 1 to 6. In somefurther related embodiment, p is 1 to 4. In some further relatedembodiment, p is 1 to 2. In still some further related embodiment, p ismore than 1. In some further embodiment, p is 6. R¹ and R² may be any ofthe embodiments described above (e.g. R¹ maybe linear unsubstitutedC₁-C₆ alkyl, R² maybe linear unsubstituted C₁-C₂ alkyl). Thus, in someembodiment, R¹ is hydrogen, o is 0 and p is 6.

In some embodiments, o is 1 to 15. In some related embodiments, o is 1to 12. In some related embodiments, o is 1 to 10. In some relatedembodiments, o is 1 to 8. In some related embodiments, o is 1 to 6. Insome related embodiments, o is 1 to 4. In some related embodiments, o is1 to 2. In some further related embodiment, p is 1 to 10. In somefurther related embodiment, p is 1 to 8. In some further relatedembodiment, p is 1 to 6. In some further related embodiment, p is 1 to4. In some further related embodiment, p is 1 to 2. In still somefurther related embodiment, p is more than 1. R¹ and R² may be any ofthe embodiments described above (e.g. R¹ maybe linear unsubstitutedC₁-C₆ alkyl, R² maybe linear unsubstituted C₁-C2 alkyl).

In some embodiments, o is 2 to 15. In some related embodiments, o is 2to 12. In some related embodiments, o is 2 to 10. In some relatedembodiments, o is 2 to 8. In some related embodiments, o is 2 to 6. Insome related embodiments, o is 2 to 4. In some further relatedembodiment, p is 1 to 10. In some further related embodiment, p is 1 to8. In some further related embodiment, p is 1 to 6. In some furtherrelated embodiment, p is 1 to 4. In some further related embodiment, pis 1 to 2. In still some further related embodiment, p is more than 1.R¹ and R² may be any of the embodiments described above (e.g. R¹ maybelinear unsubstituted C₁-C₆ alkyl, R² maybe linear unsubstituted C₁-C₂alkyl).

In some embodiments, o is 4 to 15. In some related embodiments, o is 4to 12. In some related embodiments, o is 4 to 10. In some relatedembodiments, o is 4 to 8. In some related embodiments, o is 4 to 6. Insome further related embodiment, p is 1 to 10. In some further relatedembodiment, p is 1 to 8. In some further related embodiment, p is 1 to6. In some further related embodiment, p is 1 to 4. In some furtherrelated embodiment, p is 1 to 2. In still some further relatedembodiment, p is more than 1. R¹ and R² may be any of the embodimentsdescribed above (e.g. R¹ maybe linear unsubstituted C₁-C₆ alkyl, R²maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiments, o is 6 to 15. In some related embodiments, o is 6to 12. In some related embodiments, o is 6 to 10. In some relatedembodiments, o is 6 to 8. In some further related embodiment, p is 1 to10. In some further related embodiment, p is 1 to 8. In some furtherrelated embodiment, p is 1 to 6. In some further related embodiment, pis 1 to 4. In some further related embodiment, p is 1 to 2. In stillsome further related embodiment, p is more than 1. R¹ and R² may be anyof the embodiments described above (e.g. R¹ maybe linear unsubstitutedC₁-C₆ alkyl, R² maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiments, o is 8 to 15. In some related embodiments, o is 8to 12. In some related embodiments, o is 8 to 10. In some furtherrelated embodiment, p is 1 to 10. In some further related embodiment, pis 1 to 8. In some further related embodiment, p is 1 to 6. In somefurther related embodiment, p is 1 to 4. In some further relatedembodiment, p is 1 to 2. In still some further related embodiment, p ismore than 1. R¹ and R² may be any of the embodiments described above(e.g. R¹ maybe linear unsubstituted C₁-C₆ alkyl, R² maybe linearunsubstituted C₁-C₂ alkyl).

In some embodiments, o is 10 to 15. In some related embodiments, o is 10to 12. In some further related embodiment, p is 1 to 10. In some furtherrelated embodiment, p is 1 to 8. In some further related embodiment, pis 1 to 6. In some further related embodiment, p is 1 to 4. In somefurther related embodiment, p is 1 to 2. In still some further relatedembodiment, p is more than 1. R¹ and R² may be any of the embodimentsdescribed above (e.g. R¹ maybe linear unsubstituted C₁-C₆ alkyl, R²maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiments, o is 12 to 15. In some further related embodiment,p is 1 to 10. In some further related embodiment, p is 1 to 8. In somefurther related embodiment, p is 1 to 6. In some further relatedembodiment, p is 1 to 4. In some further related embodiment, p is 1 to2. In still some further related embodiment, p is more than 1. R^(i) andR² may be any of the embodiments described above (e.g. R¹ maybe linearunsubstituted C₁-C₆ alkyl, R² maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiment, the co-solvent has the formula:

In formula (III) R¹ is defined as above (e.g. unsubstituted C₁-C₆alkyl), R² is ethyl, q is an integer from 0 to 10, r is an integer from0 to 10 and p is an integer from 1 to 10.

In some embodiment, q is 0 to 10. In some related embodiment, q is 1 to10. In some related embodiment, q is 2 to 10. In some relatedembodiment, q is 3 to 10. In some related embodiment, q is 4 to 10. Insome related embodiment, q is 5 to 10. In some related embodiment, q is6 to 10. In some related embodiment, q is 7 to 10. In some relatedembodiment, q is 8 to 10. In some related embodiment, q is 9 to 10.Moreover, in still further related embodiments, q is 0. In some furtherrelated embodiment, r is 0 to 10. In some further related embodiment, ris 1 to 10. In some further related embodiment, r is 2 to 10. In somefurther related embodiment, r is 3 to 10. In some further relatedembodiment, r is 4 to 10. In some further related embodiment, r is 5 to10. In some further related embodiment, r is 6 to 10. In some furtherrelated embodiment, r is 7 to 10. In some further related embodiment, ris 8 to 10. In some further related embodiment, r is 9 to 10. Moreover,in still further related embodiments, r is 0. In still some furtherembodiment, p is 1 to 10. In still some further embodiment, p is 2 to10. In still some further embodiment, p is 3 to 10. In still somefurther embodiment, p is 4 to 10. In still some further embodiment, p is5 to 10. In still some further embodiment, p is 6 to 10. In still somefurther embodiment, p is 7 to 10. In still some further embodiment, p is8 to 10. In still some further embodiment, p is 9 to 10. R¹ and R² maybe any of the embodiments described above (e.g. R¹ maybe linearunsubstituted C₁-C₆ alkyl or hydrogen, R² maybe linear unsubstitutedC₁-C₂ alkyl).

In some embodiment, q is 0 to 9. In some related embodiment, q is 1 to9. In some related embodiment, q is 2 to 9. In some related embodiment,q is 3 to 9. In some related embodiment, q is 4 to 9. In some relatedembodiment, q is 5 to 9. In some related embodiment, q is 6 to 9. Insome related embodiment, q is 7 to 9. In some related embodiment, q is 8to 9. Moreover, in still further related embodiments, q is 0. In somefurther related embodiment, r is 0 to 10. In some further relatedembodiment, r is 1 to 10. In some further related embodiment, r is 2 to10. In some further related embodiment, r is 3 to 10. In some furtherrelated embodiment, r is 4 to 10. In some further related embodiment, ris 5 to 10. In some further related embodiment, r is 6 to 10. In somefurther related embodiment, r is 7 to 10. In some further relatedembodiment, r is 8 to 10. In some further related embodiment, r is 9 to10. Moreover, in still further related embodiments, r is 0. In stillsome further embodiment, p is 1 to 10. In still some further embodiment,p is 2 to 10. In still some further embodiment, p is 3 to 10. In stillsome further embodiment, p is 4 to 10. In still some further embodiment,p is 5 to 10. In still some further embodiment, p is 6 to 10. In stillsome further embodiment, p is 7 to 10. In still some further embodiment,p is 8 to 10. In still some further embodiment, p is 9 to 10. R¹ and R²may be any of the embodiments described above (e.g. R¹ maybe linearunsubstituted C₁-C₆ alkyl or hydrogen, R² maybe linear unsubstitutedC₁-C₂ alkyl).

In some embodiment, q is 0 to 8. In some related embodiment, q is 1 to8. In some related embodiment, q is 2 to 8. In some related embodiment,q is 3 to 8. In some related embodiment, q is 4 to 8. In some relatedembodiment, q is 5 to 8. In some related embodiment, q is 6 to 8. Insome related embodiment, q is 7 to 8. Moreover, in still further relatedembodiments, q is 0. In some further related embodiment, r is 0 to 10.In some further related embodiment, r is 1 to 10. In some furtherrelated embodiment, r is 2 to 10. In some further related embodiment, ris 3 to 10. In some further related embodiment, r is 4 to 10. In somefurther related embodiment, r is 5 to 10. In some further relatedembodiment, r is 6 to 10. In some further related embodiment, r is 7 to10. In some further related embodiment, r is 8 to 10. In some furtherrelated embodiment, r is 9 to 10. Moreover, in still further relatedembodiments, r is 0. In still some further embodiment, p is 1 to 10. Instill some further embodiment, p is 2 to 10. In still some furtherembodiment, p is 3 to 10. In still some further embodiment, p is 4 to10. In still some further embodiment, p is 5 to 10. In still somefurther embodiment, p is 6 to 10. In still some further embodiment, p is7 to 10. In still some further embodiment, p is 8 to 10. In still somefurther embodiment, p is 9 to 10. R¹ and R² may be any of theembodiments described above (e.g. R¹ maybe linear unsubstituted C₁-C₆alkyl or hydrogen, R² maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiment, q is 0 to 7. In some related embodiment, q is 1 to7. In some related embodiment, q is 2 to 7. In some related embodiment,q is 3 to 7. In some related embodiment, q is 4 to 7. In some relatedembodiment, q is 5 to 7. In some related embodiment, q is 6 to 7.Moreover, in still further related embodiments, q is 0. In some furtherrelated embodiment, r is 0 to 10. In some further related embodiment, ris 1 to 10. In some further related embodiment, r is 2 to 10. In somefurther related embodiment, r is 3 to 10. In some further relatedembodiment, r is 4 to 10. In some further related embodiment, r is 5 to10. In some further related embodiment, r is 6 to 10. In some furtherrelated embodiment, r is 7 to 10. In some further related embodiment, ris 8 to 10. In some further related embodiment, r is 9 to 10. Moreover,in still further related embodiments, r is 0. In still some furtherembodiment, p is 1 to 10. In still some further embodiment, p is 2 to10. In still some further embodiment, p is 3 to 10. In still somefurther embodiment, p is 4 to 10. In still some further embodiment, p is5 to 10. In still some further embodiment, p is 6 to 10. In still somefurther embodiment, p is 7 to 10. In still some further embodiment, p is8 to 10. In still some further embodiment, p is 9 to 10. R¹ and R² maybe any of the embodiments described above (e.g. R¹ maybe linearunsubstituted C₁-C₆ alkyl or hydrogen, R² maybe linear unsubstitutedC₁-C₂ alkyl).

In some embodiment, q is 0 to 6. In some related embodiment, q is 1 to6. In some related embodiment, q is 2 to 6. In some related embodiment,q is 3 to 6. In some related embodiment, q is 4 to 6. In some relatedembodiment, q is 5 to 6. Moreover, in still further related embodiments,q is 0. In some further related embodiment, r is 0 to 10. In somefurther related embodiment, r is 1 to 10. In some further relatedembodiment, r is 2 to 10. In some further related embodiment, r is 3 to10. In some further related embodiment, r is 4 to 10. In some furtherrelated embodiment, r is 5 to 10. In some further related embodiment, ris 6 to 10. In some further related embodiment, r is 7 to 10. In somefurther related embodiment, r is 8 to 10. In some further relatedembodiment, r is 9 to 10. Moreover, in still further relatedembodiments, r is 0. In still some further embodiment, p is 1 to 10. Instill some further embodiment, p is 2 to 10. In still some furtherembodiment, p is 3 to 10. In still some further embodiment, p is 4 to10. In still some further embodiment, p is 5 to 10. In still somefurther embodiment, p is 6 to 10. In still some further embodiment, p is7 to 10. In still some further embodiment, p is 8 to 10. In still somefurther embodiment, p is 9 to 10. R¹ and R² may be any of theembodiments described above (e.g. R¹ maybe linear unsubstituted C₁-C₆alkyl or hydrogen, R² maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiment, q is 0 to 5. In some related embodiment, q is 1 to5. In some related embodiment, q is 2 to 5. In some related embodiment,q is 3 to 5. In some related embodiment, q is 4 to 5. Moreover, in stillfurther related embodiments, q is 0. In some further related embodiment,r is 0 to 10. In some further related embodiment, r is 1 to 10. In somefurther related embodiment, r is 2 to 10. In some further relatedembodiment, r is 3 to 10. In some further related embodiment, r is 4 to10. In some further related embodiment, r is 5 to 10. In some furtherrelated embodiment, r is 6 to 10. In some further related embodiment, ris 7 to 10. In some further related embodiment, r is 8 to 10. In somefurther related embodiment, r is 9 to 10. Moreover, in still furtherrelated embodiments, r is 0. In still some further embodiment, p is 1 to10. In still some further embodiment, p is 2 to 10. In still somefurther embodiment, p is 3 to 10. In still some further embodiment, p is4 to 10. In still some further embodiment, p is 5 to 10. In still somefurther embodiment, p is 6 to 10. In still some further embodiment, p is7 to 10. In still some further embodiment, p is 8 to 10. In still somefurther embodiment, p is 9 to 10. R¹ and R² may be any of theembodiments described above (e.g. R¹ maybe linear unsubstituted C₁-C₆alkyl or hydrogen, R² maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiment, q is 0 to 4. In some related embodiment, q is 1 to4. In some related embodiment, q is 2 to 4. In some related embodiment,q is 3 to 4. Moreover, in still further related embodiments, q is 0. Insome further related embodiment, r is 0 to 10. In some further relatedembodiment, r is 1 to 10. In some further related embodiment, r is 2 to10. In some further related embodiment, r is 3 to 10. In some furtherrelated embodiment, r is 4 to 10. In some further related embodiment, ris 5 to 10. In some further related embodiment, r is 6 to 10. In somefurther related embodiment, r is 7 to 10. In some further relatedembodiment, r is 8 to 10. In some further related embodiment, r is 9 to10. Moreover, in still further related embodiments, r is 0. In stillsome further embodiment, p is 1 to 10. In still some further embodiment,p is 2 to 10. In still some further embodiment, p is 3 to 10. In stillsome further embodiment, p is 4 to 10. In still some further embodiment,p is 5 to 10. In still some further embodiment, p is 6 to 10. In stillsome further embodiment, p is 7 to 10. In still some further embodiment,p is 8 to 10. In still some further embodiment, p is 9 to 10. R¹ and R²may be any of the embodiments described above (e.g. R¹ maybe linearunsubstituted C₁-C₆ alkyl or hydrogen, R² maybe linear unsubstitutedC₁-C₂ alkyl).

In some embodiment, q is 0 to 3. In some related embodiment, q is 1 to3. In some related embodiment, q is 2 to 3. Moreover, in still furtherrelated embodiments, q is 0. In some further related embodiment, r is 0to 10. In some further related embodiment, r is 1 to 10. In some furtherrelated embodiment, r is 2 to 10. In some further related embodiment, ris 3 to 10. In some further related embodiment, r is 4 to 10. In somefurther related embodiment, r is 5 to 10. In some further relatedembodiment, r is 6 to 10. In some further related embodiment, r is 7 to10. In some further related embodiment, r is 8 to 10. In some furtherrelated embodiment, r is 9 to 10. Moreover, in still further relatedembodiments, r is 0. In still some further embodiment, p is 1 to 10. Instill some further embodiment, p is 2 to 10. In still some furtherembodiment, p is 3 to 10. In still some further embodiment, p is 4 to10. In still some further embodiment, p is 5 to 10. In still somefurther embodiment, p is 6 to 10. In still some further embodiment, p is7 to 10. In still some further embodiment, p is 8 to 10. In still somefurther embodiment, p is 9 to 10. R¹ and R² may be any of theembodiments described above (e.g. R¹ maybe linear unsubstituted C₁-C₆alkyl or hydrogen, R² maybe linear unsubstituted C₁-C₂ alkyl).

In some embodiment, q is 0 to 2. In some related embodiment, q is 1 to2. Moreover, in still further related embodiments, q is 0. In somefurther related embodiment, r is 0 to 10. In some further relatedembodiment, r is 1 to 10. In some further related embodiment, r is 2 to10. In some further related embodiment, r is 3 to 10. In some furtherrelated embodiment, r is 4 to 10. In some further related embodiment, ris 5 to 10. In some further related embodiment, r is 6 to 10. In somefurther related embodiment, r is 7 to 10. In some further relatedembodiment, r is 8 to 10. In some further related embodiment, r is 9 to10. Moreover, in still further related embodiments, r is 0. In stillsome further embodiment, p is 1 to 10. In still some further embodiment,p is 2 to 10. In still some further embodiment, p is 3 to 10. In stillsome further embodiment, p is 4 to 10. In still some further embodiment,p is 5 to 10. In still some further embodiment, p is 6 to 10. In stillsome further embodiment, p is 7 to 10. In still some further embodiment,p is 8 to 10. In still some further embodiment, p is 9 to 10. R¹ and R²may be any of the embodiments described above (e.g. R¹ maybe linearunsubstituted C₁-C₆ alkyl or hydrogen, R² maybe linear unsubstitutedC₁-C₂ alkyl).

The aqueous composition provided herein including embodiments thereofincludes a surfactant. The surfactant provided herein may be anyappropriate surfactant useful in the field of enhanced oil recovery. Insome embodiments, the surfactant is a single surfactant type in theaqueous composition. In other embodiments, the aqueous compositionincludes a plurality of different surfactants. Where the aqueouscomposition includes a plurality of different surfactants the aqueouscomposition may include a surfactant blend. A “surfactant blend” asprovided herein is a mixture of a plurality of surfactant types. In someembodiments, the surfactant blend includes a first surfactant type, asecond surfactant type or a third surfactant type. The first, second andthird surfactant type may be independently different (e.g. anionic orcationic surfactants; or two anionic surfactants having a differenthydrocarbon chain length but are otherwise the same). Therefore, aperson having ordinary skill in the art will immediately recognize thatthe terms “surfactant” and “surfactant type(s)” have the same meaningand can be used interchangeably. In some embodiments, the plurality ofdifferent surfactants includes an anionic surfactant, a non-ionicsurfactant, a zwitterionic surfactant or a cationic surfactant. In someembodiments, the surfactant is an anionic surfactant, a non-ionicsurfactant, or a cationic surfactant. In other embodiments, theco-surfactant is a zwitterionic surfactant. “Zwitterionic” or“zwitterion” as used herein refers to a neutral molecule with a positive(or cationic) and a negative (or anionic) electrical charge at differentlocations within the same molecule. Examples for zwitterionics arewithout limitation betains and sultains.

The surfactant provided herein may be any appropriate anionicsurfactant. In some embodiments, the surfactant is an anionicsurfactant. In some embodiments, the anionic surfactant is an anionicsurfactant blend. Where the anionic surfactant is an anionic surfactantblend the aqueous composition includes a plurality (i.e. more than one)of anionic surfactant types. In some embodiments, the anionic surfactantis an alkoxy carboxylate surfactant, an alkoxy sulfate surfactant, analkoxy sulfonate surfactant, an alkyl sulfonate surfactant, an arylsulfonate surfactant or an olefin sulfonate surfactant. An “alkoxycarboxylate surfactant” as provided herein is a compound having an alkylor aryl attached to one or more alkoxylene groups (typically—CH₂—CH(ethyl)—O—, —CH₂—CH(methyl)—O—, or —CH₂—CH₂—O—) which, in turn isattached to —COO⁻ or acid or salt thereof including metal cations suchas sodium. In some embodiments, the alkoxy carboxylate surfactant hasthe formula:

In formula (IV) or (V) R¹ is substituted or unsubstituted C₈-C₁₅₀ alkylor substituted or unsubstituted aryl, R² is independently hydrogen orunsubstituted C₁—C₆ alkyl, R³ is independently hydrogen or unsubstitutedC₁—C₆ alkyl, n is an integer from 2 to 210, z is an integer from 1 to 6and M⁺ is a monovalent, divalent or trivalent cation. In someembodiments, R¹ is unsubstituted linear or branched C₈-C₃₆ alkyl. Insome embodiments, R¹ is (C₆H₅—CH₂CH₂)₃C₆H₂-(TSP), (C₆H₅—CH₂CH₂)₂C₆H₃—(DSP), (C₆H₅—CH₂CH₂)₁C₆H₄— (MSP), or substituted or unsubstitutednaphthyl. In some embodiments, the alkoxy carboxylate isC₂₈-25PO-25EO-carboxylate (i.e. unsubstituted C₂₈ alkyl attached to 25—CH₂—CH(methyl)-O— linkers, attached in turn to 25 —CH₂—CH₂—O— linkers,attached in turn to —COO⁻ or acid or salt thereof including metalcations such as sodium).

In some embodiments, the surfactant is an alkoxy sulfate surfactant. Analkoxy sulfate surfactant as provided herein is a surfactant having analkyl or aryl attached to one or more alkoxylene groups (typically—CH₂—CH(ethyl)-O—, —CH₂—CH(methyl)-O—, or —CH₂—CH₂—O—) which, in turn isattached to —SO₃ ⁻ or acid or salt thereof including metal cations suchas sodium. In some embodiment, the alkoxy sulfate surfactant has theformula R^(A)—(BO)_(e)—(PO)_(f)-(EO)_(g)—SO₃ ⁻ or acid or salt(including metal cations such as sodium) thereof, wherein R^(A) isC₈-C₃₀ alkyl, BO is —CH₂—CH(ethyl)-O—, PO is —CH₂—CH(methyl)-O—, and EOis —CH₂—CH₂—O—. The symbols e, f and g are integers from 0 to 25 whereinat least one is not zero. In some embodiment, the alkoxy sulfatesurfactant is C₁₅-13PO-sulfate (i.e. an unsubstituted C₁₅ alkyl attachedto 13 —CH₂—CH(methyl)-O— linkers, in turn attached to —SO₃ ⁻ or acid orsalt thereof including metal cations such as sodium).

In other embodiments, the alkoxy sulfate surfactant has the formula

In formula (VI) R¹ and R² are independently substituted or unsubstitutedC₈-C₁₅₀ alkyl or substituted or unsubstituted aryl. R³ is independentlyhydrogen or unsubstituted C₁-C₆ alkyl. z is an integer from 2 to 210. X⁻is

and M⁺ is a monovalent, divalent or trivalent cation. In someembodiments, R¹ is branched unsubstituted C₈-C₁₅₀. In other embodiments,R¹ is branched or linear unsubstituted C₁₂-C₁₀₀ alkyl,(C₆H₅—CH₂CH₂)₃C₆H₂-(TSP), (C₆H₅—CH₂CH₂)₂C₆H₃— (DSP), (C₆H₅—CH₂CH₂)₁C₆H₄—(MSP), or substituted or unsubstituted naphthyl. In some embodiments,the alkoxy sulfate is C₁₆-C₁₆-epoxide-15PO-10EO-sulfate (i.e. a linearunsubstituted C₁₆ alkyl attached to an oxygen, which in turn is attachedto a branched unsubstitued C₁₆ alkyl, which in turn is attached to 15—CH₂—CH(methyl)-O— linkers, in turn attached to 10 —CH₂—CH₂—O— linkers,in turn attached to —SO₃ ⁻ or acid or salt thereof including metalcations such as sodium.

The alkoxy sulfate surfactant provided herein may be an aryl alkoxysulfate surfactant. An aryl alkoxy surfactant as provided herein is analkoxy surfactant having an aryl attached to one or more alkoxylenegroups (typically —CH₂—CH(ethyl)-O—, —CH₂—CH(methyl)-O—, or —CH₂—CH₂—O—)which, in turn is attached to —SO₃ ⁻ or acid or salt thereof includingmetal cations such as sodium. In some embodiments, the aryl alkoxysulfate surfactant is (C₆H₅—CH₂CH₂)₃C₆H₂-7PO-10EO-sulfate (i.e.tri-styrylphenol attached to 7 —CH₂—CH(methyl)-O— linkers, in turnattached to 10 —CH₂—CH₂—O— linkers, in turn attached to —SO₃ ⁻ or acidor salt thereof including metal cations such as sodium).

In some embodiments, the surfactant is an unsubstituted alkyl sulfate oran unsubstituted alkyl sulfonate surfactant. An alkyl sulfate surfactantas provided herein is a surfactant having an alkyl group attached to—O—SO₃ ⁻ or acid or salt thereof including metal cations such as sodium.An alkyl sulfonate surfactant as provided herein is a surfactant havingan alkyl group attached to —SO₃ ⁻ or acid or salt thereof includingmetal cations such as sodium. In some embodiments, the surfactant is anunsubstituted aryl sulfate surfactant or an unsubstituted aryl sulfonatesurfactant. An aryl sulfate surfactant as provided herein is asurfactant having an aryl group attached to —O—SO₃ ⁻ or acid or saltthereof including metal cations such as sodium. An aryl sulfonatesurfactant as provided herein is a surfactant having an aryl groupattached to —SO₃ ⁻ or acid or salt thereof including metal cations suchas sodium. In some embodiments, the surfactant is an alkyl arylsulfonate. Non-limiting examples of alkyl sulfate surfactants, arylsulfate surfactants, alkyl sulfonate surfactants, aryl sulfonatesurfactants and alkyl aryl sulfonate surfactants useful in theembodiments provided herein are alkyl aryl sulfonates (ARS) (e.g. alkylbenzene sulfonate (ABS)), alkane sulfonates, petroleum sulfonates, andalkyl diphenyl oxide (di)sulfonates. Additional surfactants useful inthe embodiments provided herein are alcohol sulfates, alcoholphosphates, alkoxy phosphate, sulfosuccinate esters, alcoholethoxylates, alkyl phenol ethoxylates, quaternary ammonium salts,betains and sultains.

The surfactant as provided herein may be an olefin sulfonate surfactant.In some embodiments, the olefin sulfonate surfactant is an internalolefin sulfonate (IOS) or an alfa olefin sulfonate (AOS). In someembodiments, the olefin sulfonate surfactant is a C₁₀-C₃₀ (IOS). In somefurther embodiments, the olefin sulfonate surfactant is C₁₅-C₁₈ IOS. Inother embodiments, the olefin sulfonate surfactant is C₁₉-C₂₈ IOS. Wherethe olefin sulfonate surfactant is C₁₅-C₁₈ IOS, the olefin sulfonatesurfactant is a mixture (combination) of C₁₅, C₁₆, C₁₇ and C₁₈ alkene,wherein each alkene is attached to a —SO₃ ⁻ or acid or salt thereofincluding metal cations such as sodium. Likewise, where the olefinsulfonate surfactant is C₁₉-C₂₈ IOS, the olefin sulfonate surfactant isa mixture (combination) of C₁₉, C₂₀, C₂₁ C₂₂, C₂₃, C₂₄, C₂₅, C₂₆, C₂₇and C₂₈ alkene, wherein each alkene is attached to a —SO₃ ⁻ or acid orsalt thereof including metal cations such as sodium. As mentioned above,the aqueous composition provided herein may include a plurality ofsurfactants (i.e. a surfactant blend). In some embodiments, thesurfactant blend includes a first olefin sulfonate surfactant and asecond olefin sulfonate surfactant. In some further embodiments, thefirst olefin sulfonate surfactant is C₁₅-C₁₈ IOS and the second olefinsulfonate surfactant is C₁₉-C₂₈ IOS.

Useful surfactants are disclosed, for example, in U.S. Pat. Nos.3,811,504, 3,811,505, 3,811,507, 3,890,239, 4,463,806, 6,022,843,6,225,267, 7,629,299; WIPO Patent Application WO/2008/079855,WO/2012/027757 and WO/2011/094442; as well as U.S. Patent ApplicationNos. 2005/0199395, 2006/0185845, 2006/018486, 2009/0270281,2011/0046024, 2011/0100402, 2011/0190175, 2007/0191633, 2010/004843.2011/0201531, 2011/0190174, 2011/0071057, 2011/0059873, 2011/0059872,2011/0048721, 2010/0319920, and 2010/0292110. Additional usefulsurfactants are surfactants known to be used in enhanced oil recoverymethods, including those discussed in D. B. Levitt, A. C. Jackson, L.Britton and G. A. Pope, “Identification and Evaluation ofHigh-Performance EOR Surfactants,” SPE 100089, conference contributionfor the SPE Symposium on Improved Oil Recovery Annual Meeting, Tulsa,Okla., Apr. 24-26, 2006.

A person having ordinary skill in the art will immediately recognizethat many surfactants are commercially available as blends of relatedmolecules (e.g. IOS and ABS surfactants). Thus, where a surfactant ispresent within a composition provided herein, a person of ordinary skillwould understand that the surfactant may be a blend of a plurality ofrelated surfactant molecules (as described herein and as generally knownin the art).

In some embodiment, the total surfactant concentration (i.e. the totalamount of all surfactant types within the aqueous compositions andemulsion compositions provided herein) in is from about 0.05% w/w toabout 10% w/w. In other embodiments, the total surfactant concentrationin the aqueous composition is from about 0.25% w/w to about 10% w/w. Inother embodiments, the total surfactant concentration in the aqueouscomposition is about 0.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 1.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 1.25% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 1.5% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 1.75% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 2.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 2.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 3.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 3.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 4.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 4.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 5.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 5.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 6.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 6.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 7.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 7.5% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 8.0% w/w.In other embodiments, the total surfactant concentration in the aqueouscomposition is about 9.0% w/w. In other embodiments, the totalsurfactant concentration in the aqueous composition is about 10% w/w.

In some embodiments, the co-solvent is present in an amount sufficientto increase the solubility of the surfactant in the aqueous phaserealtive to the absence of the co-solvent. In other words, in thepresence of a sufficient amount of the co-solvent, the solubility of thesurfactant in the aqueous phase is higher than in the absence of theco-solvent. In other embodiments, the co-solvent is present in an amountsufficient to increase the solubility of the surfactant in the aqueousphase relative to the absence of the co-solvent. Thus, in the presenceof a sufficient amount of the co-solvent the solubility of thesurfactant in the aqueous phase is higher than in the absence of theco-solvent. In some embodiments, the co-solvent is present in an amountsufficient to decrease the viscosity of the emulsion relative to theabsence of the co-solvent.

In one embodiment, the aqueous composition further includes a viscosityenhancing water-soluble polymer. In one embodiment, the viscosityenhancing water-soluble polymer may be a biopolymer such as xanthan gumor scleroglucan, a synthetic polymer such as polyacryamide, hydrolyzedpolyarcrylamide or co-polymers of acrylamide and acrylic acid,2-acrylamido 2-methyl propane sulfonate or N-vinyl pyrrolidone, asynthetic polymer such as polyethylene oxide, or any other highmolecular weight polymer soluble in water or brine. In one embodiment,the viscosity enhancing water-soluble polymer is polyacrylamide or aco-polymer of polyacrylamide. In one embodiment, the viscosity enhancingwater-soluble polymer is a partially (e.g. 20%, 25%, 30%, 35%, 40%, 45%)hydrolyzed anionic polyacrylamide. In some further embodiment, theviscosity enhancing water-soluble polymer has a molecular weight ofapproximately about 8×10⁶. In some other further embodiment, theviscosity enhancing water-soluble polymer has a molecular weight ofapproximately about 18×10⁶. Non-limiting examples of commerciallyavailable polymers useful for the invention including embodimentsprovided herein are Florpaam 3330S and Florpaam 3360S.

The aqueous composition provided herein may further include a gas. Thus,in some embodiment, the aqueous composition further includes a gas. Forinstance, the gas may be combined with the aqueous composition to reduceits mobility by decreasing the liquid flow in the pores of the solidmaterial (e.g. rock). In some embodiments, the gas may be supercriticalcarbon dioxide, nitrogen, natural gas or mixtures of these and othergases.

In some embodiments, the aqueous composition further includes an alkaliagent. An alkali agent as provided herein is a basic, ionic salt of analkali metal (e.g. lithium, sodium, potassium) or alkaline earth metalelement (e.g. magnesium, calcium, barium, radium). In some embodiments,the alkali agent is NaOH, KOH, LiOH, Na₂CO₃, NaHCO_(3,) Na-metaborate,Na silicate, Na orthosilicate, or NH₄OH. The aqueous composition mayinclude seawater, or fresh water from an aquifer, river or lake. In someembodiments, the aqueous composition includes hard brine or soft brine.In some further embodiments, the water is soft brine. In some furtherembodiments, the water is hard brine. Where the aqueous compositionincludes soft brine, the aqueous composition may include an alkalineagent. In soft brine the alkaline agent provides for enhanced soapgeneration from the active oils, lower surfactant adsorption to thesolid material (e.g. rock) in the reservoir and increased solubility ofviscosity enhancing water soluble polymers. The alkali agent is presentin the aqueous composition at a concentration from about 0.1% w/w toabout 10% w/w.

The aqueous composition may include more than 10 ppm of divalent cationscombined. In one embodiment, the aqueous composition includes more than10 ppm of Ca²⁺ and Mg²⁺ combined. The aqueous composition may includemore than 100 ppm of divalent cations combined. In one embodiment, theaqueous composition includes more than 1000 ppm of Ca²⁺ and Mg²⁺combined. In one embodiment, the aqueous composition includes more than3000 ppm of Ca²⁺ and Mg²⁺ combined.

In one embodiment, the aqueous composition includes more than 10 ppm ofcations such as divalent cations. In other embodiments, the aqueouscomposition includes more than 100 ppm of cations such as divalentcations. In one embodiment, the aqueous composition includes more than1000 ppm of cations such as divalent cations. In one embodiment, thedivalent cations are Ba²⁺, Fe²⁺, Ca²⁺ and Mg²⁺.

In some embodiments, the aqueous composition has a pH of less than about9.5. In other embodiments, the aqueous composition has a pH of less thanabout 9.0. In other embodiments, the aqueous composition has a pH ofless than about 8.5. In other embodiments, the aqueous composition has apH of less than about 8. In other embodiments, the aqueous compositionhas a pH of less than about 7.5. In other embodiments, the aqueouscomposition has a pH of less than about 10.0. In other embodiments, theaqueous composition has a pH of less than about 11.0. In otherembodiments, the aqueous composition has a pH of less than about 12.0.

In some embodiments, the aqueous composition has a salinity of at least5,000 ppm. In other embodiments, the aqueous composition has a salinityof at least 50,000 ppm. In other embodiments, the aqueous compositionhas a salinity of at least 150,000 ppm. The total range of salinity(total dissolved solids in the brine) is 100 ppm to saturated brine(about 260,000 ppm). The aqueous composition may include seawater, brineor fresh water from an aquifer, river or lake. The aqueous combinationmay further include salt to increase the salinity. In some embodiments,the salt is NaCl, KCl, CaCl₂, or MgCl₂.

In another aspect, an emulsion composition is provided including anunrefined petroleum phase and an aqueous phase. In the emulsioncomposition the aqueous phase includes water, a surfactant and aco-solvent having the formula

In formula (I) R¹ is independently hydrogen or unsubstituted C₁-C₆alkyl, R² is independently hydrogen or unsubstituted C₁-C₂ alkyl, and nis an integer from 1 to 30. The co-solvent is a compound according tothe embodiments provided herein (e.g. a compound of formula (I), (II),or (III)). In one embodiment, the aqueous phase includes the componentsset forth in the aqueous composition provided above. For example, in oneembodiment, the aqueous phase contains water, a surfactant and aco-solvent. The aqueous phase may include a plurality of differentsurfactants. In one embodiment, the viscosity of the emulsioncomposition is less than the viscosity in the absence of the co-solvent.In one embodiment, the viscosity of the emulsion composition is lessthan 3 times the viscosity of an unrefined petroleum (e.g. the unrefinedpetroleum which makes up the unrefined petroleum phase of the emulsioncomposition). In other embodiments, the viscosity of the emulsioncomposition is less than 30 centipoise. In other embodiments, theviscosity of the emulsion composition is less than 200 centipoise. Theco-solvents present in the aqueous phase transform (break down) theinitially formed macroemulsion into stable microemulsions therebyallowing for efficient recovery of the crude oil in the petroleum phase.In one embodiment, the emulsion composition is a microemulsion. A“microemulsion” as referred to herein is a thermodynamically stablemixture of oil, water and surfactants that may also include additionalcomponents such as co-solvents, electrolytes, alkali and polymers. Incontrast, a “macroemulsion” as referred to herein is a thermodynamicallyunstable mixture of oil and water that may also include additionalcomponents.

In some embodiment, the co-solvent has the formula:

In formula (II) R¹ is defined as above (e.g. unsubstituted C₁-C₆ alkyl),R² is methyl or ethyl, o is an integer from 0 to 15 and p is an integerfrom 1 to 10. In some embodiments, R² is methyl. In other embodiments,R² is ethyl. In formula (II) R² can appear more than once and can beoptionally different. For example, in some embodiments where o is 3, R²appears three times and can be optionally different. In otherembodiments, where o is 6, R² appears six times and can be optionallydifferent.

In another aspect, an emulsion composition is provided including anunrefined petroleum phase and an aqueous phase. In the emulsioncomposition the aqueous phase includes water, a surfactant and aco-solvent having the formula:

In formula (IA) R¹ is independently hydrogen, unsubstituted C₁-C₆ alkylor R⁵—OH, R² is independently hydrogen or unsubstituted C₁-C₂ alkyl, R⁵is independently a bond or unsubstituted C₁-C₆ alkyl, n is an integerfrom 1 to 30, o is an integer from 1 to 5 and z is an integer from 1 to5.

In some embodiments, the co-solvent is present in an amount sufficientto increase the solubility of the surfactant in the aqueous phaserelative to the absence of the co-solvent. In other words, in thepresence of a sufficient amount of the co-solvent, the solubility of thesurfactant in the emulsion composition is higher than in the absence ofthe co-solvent. In other embodiments, the co-solvent is present in anamount sufficient to increase the solubility of the surfactant in theemulsion composition relative to the absence of the co-solvent. Thus, inthe presence of a sufficient amount of the co-solvent the solubility ofthe surfactant in the emulsion composition is higher than in the absenceof the co-solvent. In some embodiments, the co-solvent is present in anamount sufficient to decrease the viscosity of the emulsion relative tothe absence of the co-solvent.

In some embodiments, the emulsion composition includes a plurality ofdifferent surfactants. As described above, where the emulsioncomposition includes a plurality of different surfactants the emulsioncomposition may include a surfactant blend. A “surfactant blend” asprovided herein is a mixture of a plurality of surfactant types. In someembodiments, the surfactant blend includes a first surfactant type, asecond surfactant type or a third surfactant type. The first, second andthird surfactant type may be independently different (e.g. anionic orcationic surfactants; or two anionic surfactants having a differenthydrocarbon chain length but are otherwise the same). Therefore, aperson having ordinary skill in the art will immediately recognize thatthe terms “surfactant” and “surfactant type(s)” have the same meaningand can be used interchangeably. In some embodiments, the plurality ofdifferent surfactants includes an anionic surfactant, a non-ionicsurfactant, a zwitterionic surfactant or a cationic surfactant.

As described above the aqueous composition provided herein includingembodiments thereof may include a viscosity enhancing water solublepolymer, a gas and/or an alkali agent. Thus, in some embodiments, theemulsion composition further includes a viscosity enhancing watersoluble polymer. In other embodiments, the emulsion composition furtherincludes a gas. In some embodiments, the emulsion composition furtherincludes an alkali agent. In some embodiments, the emulsion compositionhas a pH of less than 9.5.

In some embodiments, the unrefined petroleum phase includes a nonactiveoil.

As described herein the aqueous compositions provided herein includewater, a surfactant and a co-solvent having the formula (I), (II), or(III). In one embodiment, the aqueous composition includes water, afirst surfactant having the formula (V), wherein R¹ is 28, n is 55(45-CH₂—CH(methyl)-O-linkers attached in turn to 10 —CH₂—CH₂—O—linkers), z is 1 and M is Na⁺, present at 0.2% (w/w); a secondsurfactant, wherein the second surfactant is the olefin sulfonatesurfactant C₁₉-C₂₈ IOS, present at 0.3% (w/w); and a cosolvent havingthe formula (I), wherein R¹ and R² are hydrogen and n is 6, present at0.25% (w/w).

In another embodiment, the aqueous composition includes water, a firstsurfactant having the formula R^(A)—(BO)_(e)—(PO)_(f)-(EO)_(g)—SO₃ ⁻,wherein R^(A) is a C₁₂ alkyl, e and g are 0 and f is 13; a secondsurfactant having the formula R^(A)—(BO)_(e)—(PO)_(f)-(EO)_(g)—SO₃ ³¹ ,wherein R^(A) is a C₁₃ alkyl, e and g are 0 and f is 13, wherein thecombined total amount of the first surfactant and the second surfactantis 0.5% (w/w); a third surfactant, wherein the second surfactant is theolefin sulfonate surfactant C₁₉-C₂₃ IOS, present at 0.5% (w/w); and acosolvent having the formula (I), wherein R¹ and R² are hydrogen and nis 6, present at 0.5% (w/w).

III. METHODS

In another aspect, a method of displacing an unrefined petroleummaterial in contact with a solid material is provided. The methodincludes contacting an unrefined petroleum material with an aqueouscomposition, wherein the unrefined petroleum material is in contact witha solid material. The unrefined petroleum material is allowed toseparate from the solid material thereby displacing the unrefinedpetroleum material in contact with the solid material. In someembodiments, the method further includes contacting the solid materialwith the aqueous composition. The aqueous composition includes water, asurfactant and a co-solvent (as described herein). In other embodiments,the aqueous composition further includes a water-soluble polymer. Inother embodiments, the aqueous composition further includes a gas. Inother embodiments, the aqueous composition further includes an alkaliagent. In one embodiment, the co-solvent has the formula (I). In otherembodiments, the co-solvent has the formula (II). In one embodiment, theco-solvent has the formula (III). The co-solvent may be present in anaqueous composition or an emulsion composition as described above. Insome embodiments, the co-solvent is present in an amount sufficient toincrease the solubility of the surfactant relative to the absence of theco-solvent. In some embodiments, the co-solvent is present in an amountsufficient to decrease the viscosity of the emulsion relative to theabsence of the co-solvent.

The solid material may be a natural solid material (i.e. a solid foundin nature such as rock). The natural solid material may be found in apetroleum reservoir. In one embodiment, the method is an enhanced oilrecovery method. In one embodiment, the natural solid material is rockor regolith. The natural solid material may be a geological formationsuch as clastics or carbonates. The natural solid material may be eitherconsolidated or unconsolidated material or mixtures thereof. Theunrefined active petroleum material may be trapped or confined by“bedrock” above or below the natural solid material. The unrefinedactive petroleum material may be found in fractured bedrock or porousnatural solid material. In other embodiments, the regolith is soil. Insome embodiments, the method is an enhanced oil recovery method.

In one embodiment, an emulsion forms after the contacting. The emulsionthus formed may be the emulsion composition as described above. In oneembodiment, the method includes allowing an unrefined petroleum acidwithin the unrefined petroleum material to enter into the emulsion (e.g.emulsion composition), thereby converting the unrefined petroleum acidinto a surfactant. In other words, where the unrefined petroleum acidconverts into a surfactant, the oil may be mobilized and thereforeseparated from the solid material. In some embodiments, the unrefinedpetroleum material is nonactive oil.

In another aspect, a method of converting an unrefined petroleum acidinto a surfactant is provided. The method includes contacting anunrefined petroleum material with the aqueous composition, therebyforming an emulsion in contact with the unrefined petroleum material. Anunrefined petroleum acid within the unrefined active petroleum materialis allowed to enter the emulsion, thereby converting the unrefinedpetroleum acid into a surfactant. The aqueous composition includeswater, a surfactant and a co-solvent as described herein. In somefurther embodiments, the aqueous composition includes a water-solublepolymer. In some further embodiments, the aqueous composition includes agas. In some further embodiments, the aqueous composition includes agas. In one embodiment, the co-solvent has the formula (I). In otherembodiments, the co-solvent has the formula (II). In one embodiment, theco-solvent has the formula (III). Thus, in one embodiment, the aqueouscomposition is the aqueous composition described above. And in oneembodiment, the emulsion is the emulsion composition described above. Anunrefined petroleum acid within the unrefined petroleum material isallowed to enter the emulsion, thereby converting (e.g. mobilizing) theunrefined petroleum acid into a surfactant. In one embodiment, theunrefined active petroleum material is in a petroleum reservoir. In oneembodiment, the unrefined petroleum material includes a nonactive oil.

IV. EXAMPLES

Phase Behavior Procedures

Phase Behavior Screening: Phase behavior studies have been used tocharacterize chemicals for EOR. There are many benefits in using phasebehavior as a screening method. Phase Behavior studies are used todetermine: (1) the effect of electrolytes; (2) oil solubilization andIFT reduction, (3) microemulsion densities; (4) microemulsionviscosities; (5) coalescence times; (6) optimal light co-solvent/alkaliagent formulations; and/or (7) optimal properties for recovering oilfrom cores and reservoirs.

Thermodynamically stable phases can form with oil, water andnon-surfactant aqueous mixtures. In situ generated soaps form micellarstructures at concentrations at or above the critical micelleconcentration (CMC). The emulsion coalesces into a separate phase at theoil-water interface and is referred to as a microemulsion. Amicroemulsion is a surfactant-rich distinct phase consisting of in situgenerated soaps, oil and water and light co-solvent, alkali agent andother components. This phase is thermodynamically stable in the sensethat it will return to the same phase volume at a given temperature.Some workers in the past have added additional requirements, but for thepurposes of this engineering study, the only requirement will be thatthe microemulsion is a thermodynamically stable phase.

The phase transition is examined by keeping all variables fixed exceptfor the scanning variable. The scan variable is changed over a series ofpipettes and may include, but is not limited to, salinity, temperature,chemical (light co-solvent, alcohol, electrolyte), oil, which issometimes characterized by its equivalent alkane carbon number (EACN),and light co-solvent structure, which is sometimes characterized by itshydrophilic-lipophilic balance (HLB). The phase transition was firstcharacterized by Winsor (1954) into three regions: Type I—excess oilphase, Type III—aqueous, microemulsion and oil phases, and the TypeII—excess aqueous phase. The phase transition boundaries and some commonterminology are described as follows: Type I to III—lower criticalsalinity, Type III to II—upper critical salinity, oil solubilizationratio (Vo/Vs), water solubilization ratio (Vw/Vs), the solubilizationvalue where the oil and water solubilization ratios are equal is calledthe Optimum Solubilization Ratio (σ*), and the electrolyte concentrationwhere the optimum solubilization ratio occurs is referred to as theOptimal Salinity (S*). Since no surfactant is added, the only surfactantpresent is the in-situ generated soap. For the purpose of calculating asolubilization ratio, one can assume a value for soap level usingTAN(total acid number) and an approximate molecular weight for the soap.

Determining Interfacial Tension

Efficient use of time and lab resources can lead to valuable resultswhen conducting phase behavior scans. A correlation between oil andwater solubilization ratios and interfacial tension was suggested byHealy and Reed (1976) and a theoretical relationship was later derivedby Chun Huh (1979). Lowest oil-water IFT occurs at optimumsolubilization as shown by the Chun Huh theory. This is equated to aninterfacial tension through the Chun Huh equation, where IFT varies withthe inverse square of the solubilization ratio:

$\begin{matrix}{\gamma = \frac{C}{\sigma^{2}}} & (1)\end{matrix}$

For most crude oils and microemulsions, C=0.3 is a good approximation.Therefore, a quick and convenient way to estimate IFT is to measurephase behavior and use the Chun-Huh equation to calculate IFT. The IFTbetween microemulsions and water and/or oil can be very difficult andtime consuming to measure and is subject to larger errors, so using thephase behavior approach to screen hundreds of combinations of lightco-solvents, electrolytes, oil, and so forth is not only simpler andfaster, but avoids the measurement problems and errors associated withmeasuring IFT especially of combinations that show complex behavior(gels and so forth) and will be screened out anyway. Once a goodformulation has been identified, then it is still a good idea to measureIFT.

Equipment

Phase behavior experiments are created with the following materials andequipment.

-   Mass Balance: Mass balances are used to measure chemicals for    mixtures and determine initial saturation values of cores.-   Water Deionizer: Deionized (DI) water is prepared for use with all    the experimental solutions using a Nanopure™ filter system. This    filter uses a recirculation pump and monitors the water resistivity    to indicate when the ions have been removed. Water is passed through    a 0.45 micron filter to eliminate undesired particles and    microorganisms prior to use.-   Borosilicate Pipettes: Standard 5 mL borosilicate pipettes with 0.1    mL markings are used to create phase behavior scans as well as run    dilution experiments with aqueous solutions. Ends are sealed using a    propane and oxygen flame.-   Pipette Repeater: An Eppendorf Repeater Plus® instrument is used for    most of the pipetting. This is a handheld dispenser calibrated to    deliver between 25 microliter and 1 ml increments. Disposable tips    are used to avoid contamination between stocks and allow for ease of    operation and consistency.-   Propane-oxygen Torch: A mixture of propane and oxygen gas is    directed through a Bernz-O-Matic flame nozzle to create a hot flame    about ½ inch long. This torch is used to flame-seal the glass    pipettes used in phase behavior experiments.-   Convection Ovens: Several convection ovens are used to incubate the    phase behaviors and core flood experiments at the reservoir    temperatures. The phase behavior pipettes are primarily kept in Blue    M and Memmert ovens that are monitored with mercury thermometers and    oven temperature gauges to ensure temperature fluctuations are kept    at a minimal between recordings. A large custom built flow oven was    used to house most of the core flood experiments and enabled fluid    injection and collection to be done at reservoir temperature.-   pH Meter: An ORION research model 701/digital ion analyzer with a pH    electrode is used to measure the pH of most aqueous samples to    obtain more accurate readings. This is calibrated with 4.0, 7.0 and    10.0 pH solutions. For rough measurements of pH, indicator papers    are used with several drops of the sampled fluid.

Phase Behavior Calculations

The oil and water solubilization ratios are calculated from interfacemeasurements taken from phase behavior pipettes. These interfaces arerecorded over time as the mixtures approached equilibrium and the volumeof any macroemulsions that initially formed decreased or disappeared.

Phase Behavior Methodology

The methods for creating, measuring and recording observations aredescribed in this section. Scans are made using a variety of electrolytemixtures described below. Oil is added to most aqueous non-surfactantsolutions to see if a microemulsion formed, how long it took to form andequilibrate if it formed, what type of microemulsion formed and some ofits properties such as viscosity. However, the behavior of aqueousmixtures without oil added is also important and is also done in somecases to determine if the aqueous solution is clear and stable overtime, becomes cloudy or separated into more than one phase.

Preparation of samples. Phase behavior samples are made by firstpreparing non-surfactant aqueous stock solutions and combining them withbrine stock solutions in order to observe the behavior of the mixturesover a range of salinities.

Solution Preparation. Non-surfactant aqueous stock solutions are basedon active weight-percent co-solvent. The masses of light co-solvent,alkali agent and de-ionized water (DI) are measured out on a balance andmixed in glass jars using magnetic stir bars. The order of addition isrecorded on a mixing sheet along with actual masses added and the pH ofthe final solution. Brine solutions are created at the necessary weightpercent concentrations for making the scans.

Co-solvent Stock. The chemicals being tested are first mixed in aconcentrated stock solution that usually consisted of light co-solvent,alkali agent and/or polymer along with de-ionized water. The quantity ofchemical added is calculated based on activity and measured by weightpercent of total solution. Initial experiments are at about 1-3% lightco-solvent so that the volume of the middle microemulsion phase would belarge enough for accurate measurements assuming a solubilization ratioof at least 10 at optimum salinity.

Polymer Stock. Often these stocks were quite viscous and made pipettingdifficult so they are diluted with de-ionized water accordingly toimprove ease of handling. Mixtures with polymer are made only for thoselight co-solvent formulations that showed good behavior and meritedadditional study for possible testing in core floods. Consequently,scans including polymer are limited since they are done only as a finalevaluation of compatibility with the light co-solvent.

Pipetting Procedure. Phase behavior components are added volumetricallyinto 5 ml pipettes using an Eppendorf Repeater Plus or similar pipettinginstrument. Light co-solvent, alkali agent and brine stocks are mixedwith DI water into labeled pipettes and brought to temperature beforeagitation. Almost all of the phase behavior experiments are initiallycreated with a water oil ratio (WOR) of 1:1, which involves mixing 2 mlof the aqueous phase with 2 ml of the evaluated crude oil orhydrocarbon, and different WOR experiments are mixed accordingly. Thetypical phase behavior scan consisted of 10-20 pipettes, each pipettebeing recognized as a data point in the series.

Order of Addition. Consideration must be given to the addition of thecomponents since the concentrations are often several folds greater thanthe final concentration. Therefore, an order is established to preventany adverse effects resulting from light co-solvent, alkali agent orpolymer coming into direct contact with the concentrated electrolytes.The desired sample compositions are made by combining the stocks in thefollowing order: (1) Electrolyte stock(s); (2) De-ionized water; (3)light co-solvent stock; (4) alkali agent stock; (5) Polymer stock; and(6) Crude oil or hydrocarbon.

Initial Observations. Once the components are added to the pipettes,sufficient time is allotted to allow all the fluid to drain down thesides. Then aqueous fluid levels are recorded before the addition ofoil. These measurements are marked on record sheets. Levels andinterfaces are recorded on these documents with comments over severaldays and additional sheets are printed as necessary.

Sealing and Mixing. The pipettes are blanketed with argon gas to preventthe ignition of any volatile gas present by the flame sealing procedure.The tubes are then sealed with the propane-oxygen torch to prevent lossof additional volatiles when placed in the oven. Pipettes are arrangedon the racks to coincide with the change in the scan variable. Once thephase behavior scan is given sufficient time to reach reservoirtemperature (15-30 minutes), the pipettes are inverted several times toprovide adequate mixing. Tubes are observed for low tension upon mixingby looking at droplet size and how uniform the mixture appeared. Thenthe solutions are allowed to equilibrate over time and interface levelsare recorded to determine equilibration time and light co-solvent/alkaliagent performance.

Measurements and Observations. Phase behavior experiments are allowed toequilibrate in an oven that is set to the reservoir temperature for thecrude oil being tested. The fluid levels in the pipettes are recordedperiodically and the trend in the phase behavior observed over time.Equilibrium behavior is assumed when fluid levels ceased to changewithin the margin of error for reading the samples.

Fluid Interfaces. The fluid interfaces are the most crucial element ofphase behavior experiments. From them, the phase volumes are determinedand the solubilization ratios are calculated. The top and bottominterfaces are recorded as the scan transitioned from an oil-in-watermicroemulsion to a water-in-oil microemulsion. Initial readings aretaken one day after initial agitation and sometimes within hours ofagitation if coalescence appeared to happen rapidly. Measurements aretaken thereafter at increasing time intervals (for example, one day,four days, one week, two weeks, one month and so on) until equilibriumis reached or the experiment is deemed unessential or uninteresting forcontinued observation.

V. TABLES

TABLE 1 Effect of many variables on emulsion viscosity and stabilityViscosity Stability Heavy Crude Oil Oil %¹ ↑ ↑ ↑ Viscosity² ↑ minor ?effect Composition³ Aqueous Salinity⁴ ↑ ↑ ? Alkali Conc.^(5a) NaOH ↑ ↑ ↑Na2CO3^(5b) ↑ ↑ ↑ Co-solvent Type⁶ Concentration⁷ ↑ ↓ ? # of EO's⁸ ↑Minor ? effect Shear rate in ↑ ↓ ? pipeline⁹ Environmental Temp of ↑ ↓ ↓Transport¹⁰ Time of ↑ ↓ storage¹¹ Emulsion Prep Temp of ↑ ↓ ↑ Proceduremixing¹² Mixing time¹² ↑ ↑ ↑ Mixing ↑ ↑ ↑ speed¹²

VI. EMBODIMENTS

Embodiment 1. An aqueous composition comprising water, a surfactant anda co-solvent having the formula:

wherein R¹ is independently hydrogen or unsubstituted C₁-C₆ alkyl; R² isindependently hydrogen or unsubstituted C₁-C2 alkyl; and n is an integerfrom 1 to 30.

Embodiment 2. The aqueous composition of embodiment 1, wherein R¹ isunsubstituted C2-C6 alkyl.

Embodiment 3. The aqueous composition of any one of embodiments 1 or 2,wherein R¹ is unsubstituted C₄-C₆ alkyl.

Embodiment 4. The aqueous composition of any of the precedingembodiments, wherein R¹ is unsubstituted C₂ alkyl.

Embodiment 5. The aqueous composition of any of the precedingembodiments, wherein R¹ is methyl.

Embodiment 6. The aqueous composition of any of the precedingembodiments, wherein R¹ is hydrogen.

Embodiment 7. The aqueous composition of any of the precedingembodiments, wherein R² is hydrogen.

Embodiment 8. The aqueous composition of any of the precedingembodiments, wherein R² is methyl.

Embodiment 9. The aqueous composition of any of the precedingembodiments, wherein R² is ethyl.

Embodiment 10. The aqueous composition of any of the precedingembodiments, wherein n is an integer from 1 to 10.

Embodiment 11. The aqueous composition of any of the precedingembodiments, wherein R¹ is hydrogen and n is 6.

Embodiment 12. The aqueous composition of any of the precedingembodiments, wherein R¹ is hydrogen and n is 6.

Embodiment 13. The aqueous composition of any of the precedingembodiments, wherein said co-solvent has the formula:

wherein R² is methyl or ethyl; o is an integer from 0 to 15; and p is aninteger from 1 to 10.

Embodiment 14. The aqueous composition of any of the precedingembodiments, wherein R¹ is hydrogen, o is 0 and p is 6.

Embodiment 15. The aqueous composition of any of the precedingembodiments, wherein said co-solvent has the formula:

wherein R¹ is ethyl; q is an integer from 0 to 10; r is an integer from0 to 10; and p is an integer from 1 to 10.

Embodiment 16. The aqueous composition of any of the precedingembodiments, comprising a plurality of different surfactants.

Embodiment 17. The aqueous composition of embodiment 16, wherein saidplurality of different surfactants comprises an anionic surfactant, anon-ionic surfactant, a zwitterionic surfactant or a cationicsurfactant.

Embodiment 18. The aqueous composition of embodiment 17, wherein saidanionic surfactant is an alkoxy carboxylate surfactant, an alkoxysulfate surfactant, an alkoxy sulfonate surfactant, an alkyl sulfonatesurfactant, an aryl sulfonate surfactant or an olefin sulfonatesurfactant.

Embodiment 19. The aqueous composition of any of the precedingembodiments, wherein said co-solvent is present in an amount sufficientto increase the solubility of said surfactant in said aqueouscomposition relative to the absence of said co-solvent.

Embodiment 20. The aqueous composition of any of the precedingembodiments, further comprising a viscosity enhancing water solublepolymer.

Embodiment 21. The aqueous composition of embodiment 20, wherein saidviscosity enhancing water soluble polymer is polyacrylamide or aco-polymer of polyacrylamide.

Embodiment 22. The aqueous composition of any of the precedingembodiments, further comprising a gas.

Embodiment 23. The aqueous composition of any of the precedingembodiments, further comprising an alkali agent.

Embodiment 24. The aqueous composition of embodiment 23, wherein saidalkali agent is NaOH, KOH, LiOH, Na₂CO₃, NaHCO₃, Na-metaborate, Nasilicate, Na orthosilicate or NH₄OH.

Embodiment 25. The aqueous composition of any of the precedingembodiments, comprising more than 10 ppm of Ca²⁺ and Mg²⁺ combined.

Embodiment 26. The aqueous composition of any of the precedingembodiments, comprising more than 100 ppm of Ca²⁺ and Mg²⁺ combined.

Embodiment 27. The aqueous composition of any of the precedingembodiments, comprising more than 1000 ppm of Ca²⁺ and Mg²⁺ combined.

Embodiment 28. The aqueous composition of any of the precedingembodiments, having a pH of less than 9.5.

Embodiment 29. The aqueous composition of any of the precedingembodiments, having a salinity of at least 5,000 ppm.

Embodiment 30. The aqueous composition of any of the precedingembodiments, having a salinity of at least 50,000 ppm.

Embodiment 31. The aqueous composition of any of the precedingembodiments, having a salinity of at least 150,000 ppm.

Embodiment 32. An emulsion composition comprising an unrefined petroleumphase and an aqueous phase, wherein said aqueous phase comprises water,a surfactant and a co-solvent having the formula:

wherein R¹ is independently hydrogen or unsubstituted C₁-C₆ alkyl; R² isindependently hydrogen or unsubstituted C₁-C₂ alkyl; and n is an integerfrom 1 to 30.

Embodiment 33. The emulsion composition of embodiment 32, wherein saidco-solvent has the formula:

wherein R² is methyl or ethyl; o is an integer from 0 to 15; and p is aninteger from 1 to 10.

Embodiment 34. The emulsion composition of embodiments 15 or 33, whereinsaid emulsion composition is a microemulsion.

Embodiment 35. The emulsion composition of any one of embodiments 32-34,wherein said co-solvent is present in an amount sufficient to increasethe solubility of said surfactant in said aqueous phase relative to theabsence of said co-solvent.

Embodiment 36. The emulsion composition of any one of embodiments 32-35,comprising a plurality of different surfactants.

Embodiment 37. The emulsion composition of embodiment 36, wherein saidplurality of different surfactants comprises an anionic surfactant, anon-ionic surfactant, a zwitterionic surfactant or a cationicsurfactant.

Embodiment 38. The emulsion composition of any one of embodiments 32-37,further comprising a viscosity enhancing water soluble polymer.

Embodiment 39. The emulsion composition of any one of embodiments 32-38,further comprising a gas.

Embodiment 40. The emulsion composition of any one of embodiments 32-39,further comprising an alkali agent.

Embodiment 41. The emulsion composition of any one of embodiments 32-40,having a pH of less than 9.5.

Embodiment 42. The emulsion composition of any one of embodiments 32-41,wherein said unrefined petroleum phase comprises a nonactive oil.

Embodiment 43. A method of displacing an unrefined petroleum material incontact with a solid material, said method comprising: (i) contacting anunrefined petroleum material with the aqueous composition of one ofembodiments 1 to 31, wherein said unrefined petroleum material is incontact with a solid material; (ii) allowing said unrefined petroleummaterial to separate from said solid material thereby displacing saidunrefined petroleum material in contact with said solid material.

Embodiment 44. The method of embodiment 43, further comprisingcontacting said solid material with said aqueous composition.

Embodiment 45. The method of any one of embodiments 43-44, wherein saidco-solvent is present in an amount sufficient to increase the solubilityof said surfactant relative to the absence of said co-solvent.

Embodiment 46. The method of any one of embodiments 43-45, wherein saidmethod is an enhanced oil recovery method.

Embodiment 47. The method of any one of embodiments 43-46, wherein saidnatural solid material is rock or regolith.

Embodiment 48. The method of any one of embodiments 47, wherein saidregolith is soil.

Embodiment 49. The method of any one of embodiments 43-48, wherein anemulsion forms after said contacting.

Embodiment 50. The method of any one of embodiments 43-49, wherein saidunrefined petroleum material is a nonactive oil.

Embodiment 51. A method of converting an unrefined petroleum acid into asurfactant, said method comprising: (i) contacting a petroleum materialwith the aqueous composition of one of embodiments 1 to 31, therebyforming an emulsion in contact with said petroleum material;

(ii) allowing an unrefined petroleum acid within said unrefinedpetroleum material to enter into said emulsion, thereby converting saidunrefined petroleum acid into a surfactant.

Embodiment 52. The method of embodiment 51, wherein said unrefinedpetroleum material is in a petroleum reservoir.

Embodiment 53. The method of embodiment 51, wherein said unrefinedpetroleum material comprises a nonactive oil.

What is claimed is:
 1. An aqueous composition comprising water, asurfactant and a co-solvent having the formula:

wherein R¹ is independently hydrogen or unsubstituted C₁-C₆ alkyl; R² isindependently hydrogen or unsubstituted C₁-C₂ alkyl; and n is an integerfrom 1 to
 30. 2. The aqueous composition of claim 1, wherein R¹ isunsubstituted C₂-C₆ alkyl.
 3. The aqueous composition of claim 1,wherein R¹ is hydrogen.
 4. The aqueous composition of claim 1, whereinR² is hydrogen.
 5. The aqueous composition of claim 1, wherein n is aninteger from 1 to
 10. 6. The aqueous composition of claim 1, wherein R¹is hydrogen and n is
 6. 7. The aqueous composition of claim 1, whereinsaid co-solvent has the formula:

wherein R² is methyl or ethyl; o is an integer from 0 to 15; and p is aninteger from 1 to
 10. 8. The aqueous composition of claim 7, wherein R¹is hydrogen, o is O and p is
 6. 9. The aqueous composition of claim 1,comprising a plurality of different surfactants.
 10. The aqueouscomposition of claim 9, wherein said plurality of different surfactantscomprises an anionic surfactant, a non-ionic surfactant, a zwitterionicsurfactant or a cationic surfactant.
 11. The aqueous composition ofclaim 1, further comprising a viscosity enhancing water soluble polymer.12. The aqueous composition of claim 1, further comprising an alkaliagent.
 13. The aqueous composition of claim 12, wherein said alkaliagent is NaOH, KOH, LiOH, Na₂CO₃, NaHCO₃, Na-metaborate, Na silicate, Naorthosilicate or NH₄OH.
 14. The aqueous composition of claim 1, having apH of less than 9.5.
 15. An emulsion composition comprising an unrefinedpetroleum phase and an aqueous phase, wherein said aqueous phasecomprises water, a surfactant and a co-solvent having the formula:

wherein R¹ is independently hydrogen or unsubstituted C₁-C₆ alkyl; R² isindependently hydrogen or unsubstituted C₁-C₂ alkyl; and n is an integerfrom 1 to
 30. 16. The emulsion composition of claim 15, wherein saidco-solvent has the formula:

wherein R² is methyl or ethyl; o is an integer from 0 to 15; and p is aninteger from 1 to
 10. 17. The emulsion composition of claim 15,comprising a plurality of different surfactants.
 18. The emulsioncomposition of claim 17, wherein said plurality of different surfactantscomprises an anionic surfactant, a non-ionic surfactant, a zwitterionicsurfactant or a cationic surfactant.
 19. The emulsion composition ofclaim 15, further comprising an alkali agent.
 20. The emulsioncomposition of claim 15, having a pH of less than 9.5.
 21. The emulsioncomposition of claim 15, wherein said unrefined petroleum phasecomprises a nonactive oil.
 22. A method of displacing an unrefinedpetroleum material in contact with a solid material, said methodcomprising: (i) contacting an unrefined petroleum material with theaqueous composition of claim 1, wherein said unrefined petroleummaterial is in contact with a solid material; (ii) allowing saidunrefined petroleum material to separate from said solid materialthereby displacing said unrefined petroleum material in contact withsaid solid material.
 23. The method of claim 22, further comprisingcontacting said solid material with said aqueous composition.
 24. Themethod of claim 22, wherein said method is an enhanced oil recoverymethod.
 25. The method of claim 22, wherein an emulsion forms after saidcontacting.
 26. The method of claim 22, wherein said unrefined petroleummaterial is a nonactive oil.
 27. A method of converting an unrefinedpetroleum acid into a surfactant, said method comprising: (i) contactinga petroleum material with the aqueous composition of one of claim 1,thereby forming an emulsion in contact with said petroleum material;(ii) allowing an unrefined petroleum acid within said unrefinedpetroleum material to enter into said emulsion, thereby converting saidunrefined petroleum acid into a surfactant.
 28. The method of claim 27,wherein said unrefined petroleum material is in a petroleum reservoir.29. The method of claim 27, wherein said unrefined petroleum materialcomprises a nonactive oil.